A determination of the location of a mobile device is required as part of the processing of an emergency call, such as a E911 call, from the mobile device. Location information (e.g. street address) is provided for the personnel at a public safety answering point (PSAP) that receives the call, to allow a call taker to dispatch assistance in response to the emergency. The location information is based on positional information (e.g. latitude and longitude) provided to the PSAP via a position determining element (PDE) which provides the positional information of the mobile device for updating an automatic location identification (ALI) database. The PDE may be network based, such as part of a mobile positioning center (MPC) within a mobile communication network serving the mobile device; or the PDE may be implemented at the mobile device, such as a global positioning system (GPS) chip in the mobile device. Whether in the network or the mobile device, the PDE determines the position of the mobile device based on information received from the mobile device and/or the mobile communication network serving the mobile device. The PDE provides the positional information to the MPC and the MPC updates a corresponding record in the ALI database. When the PSAP receives the E911 call, the PSAP queries the ALI database, receives the positional information from the ALI database, determines the location of the mobile device based on the positional information, and displays the positional information along with the location to the call taker.
The PDE receives information from the mobile device and/or the mobile communication network via various protocols. Most often, an individual PDE implements support for multiple protocols. A mobile device based PDE, for example, supports a protocol for receiving GPS information from a GPS receiver in the mobile device and a protocol for receiving timing information from the mobile communication network. The mobile device based PDE, however, may not support all of the various protocols for determining positional information of the mobile device. In addition, in some situations, the protocols supported by the mobile device based PDE may not successfully provide the necessary information for the mobile device based PDE to determine the position of the mobile device. In these situations, the MPC must rely on a network based PDE, which requires the mobile device to utilize a particular mobile network access technology.
Hence a need exists for a way to identify when a mobile device based PDE is unable to determine the mobile device position and ensure the mobile device is utilizing the mobile network access technology that will allow the MPC to provide positional information to the ALI database.